Left ventricular assist device (LVAD) support allows the neonate with congenital heart disease or cardiomyopathy to grow to a larger body weight that is more feasible for complex surgical correction or heart transplant. The Berlin Heart ExCOR, is FDA-approved for pediatric LVAD application. Although this device is outside the body, the outflow graft may still create coronary artery/heart compression. Our ultimate goal is to develop a less invasive and dependable LVAD system for the neonate as well as older pediatric patients. The enabling technology is a double lumen cannula (DLC), which is inserted from the apex into the aorta. Coupled with an existing blood pump, this DLC withdraws blood from the LV and delivers blood into the aorta, unloading the LV. Our DLC-based LVAD only requires a one site, less invasive apex cannulation. The advantages are: 1) no outflow graft and associated heart/coronary artery compression; 2) no need of cardiopulmonary bypass and associated blood transfusion; 3) reserves more invasive sternotomy for future complex heart surgery. This transapical to aorta (TAA) DLC enables a high performance paracorporeal/ extracorporeal LVAD and allows addition of a gas exchanger for cyanotic heart disease. Our Phase I study proved that the TAA DLC-based neonate LVAD system was very easy to implant via a small left thoracotomy and efficiently unloaded the LV for 6 hours with no increase in free hemoglobin and no decrease in hemoglobin and platelet counts. Phase II SBIR objective: Based on the Phase I results, we will optimize the design and fabricate a final commercial quality TAA DLC prototype for even smaller neonate application and for 5 day survival lamb studies. Specific Aim 1: To design, fabricate, and bench-test the high efficiency, commercial quality TAA DLC prototype for smaller neonate application and for 5 day survival in vivo lamb studies. The TAA DLC will be made of one piece reinforced polyurethane. Computational fluid dynamics will be used to optimize the DLC design. A DLC anchoring system will be also developed to secure TAA DLC on apex and chest wall for long-term ambulatory use. A 13 Fr/10 Fr TAA DLC will be developed for 2-4 kg neonate lamb acute study and a 19 Fr/15 Fr TAA DLC will developed for 4 week old lamb (20 kg) survival study. The final prototype will be tested for performance, reliability, and hemolysis. Thirty day durability will be tested in 37% glycerin. Specific Aim 2: To test new 13/10 Fr TAA DLC-based LVAD in 2- 4 kg neonate lamb (n=5). This 6 hour study is designed to prove TAA DLC suitable for clinical neonate LVAD application. We will investigate ease of TAA deployment and in vivo performance, as well as potential aortic valve obstruction by extension infusion cannula. Specific Aim 3: To test the TAA DLC prototype for 5 days LVAD application in 4 weeks old neonate lamb (n=5). The 4 week old lamb is still considered a neonate but almost fully weaned, allowing us to perform 5 day survival study. This in vivo study will test performance, reliability, durability, and biocompatibility. Upon this SBIR grant completion, the commercialized TAA DLC will provide a less invasive neonate LVAD.